odd clutch problem

I have a 91 LS with 155000 miles on it. Over the past 10-15000 miles the clutch's engagement point has gone from halfway through the pedal's travel to the very top, to the point where the clutch will disengage from almost no pressure on the pedal, and has to be completely released to engage fully. It doesn't seem to be a clutch problem, and as I was reading my manual I came across some info about the clutch trailing arm, which is supposed to be checked every 7500 miles. Is this the problem, or is it a failing clutch cylinder, or perhaps even the clutch itself?

You don't have a clutch cylinder, you have a cable clutch. What you need to do is determine if it needs to be adjusted, if you look down at the front of the tranny you will see where the clutch arm sticks out ot the tranny. There is a cable attached there and you just adjust the locking nuts so that there is more tention on the cable. Try reading in the manual about it, it should tell you exactly how to do it.